The ingredient Cystine is found in new drug TBX-FREE. It's used to stop smoking,how does it work?

How does Cystine work and what is used for? TBX-FREE is seen as a medicine used to stop smoking, Cystine is the ingredient in this.TBX-FREE is new drug to stop smoking without nicotine, the only drug found . Need to know about the main ingredient Cystine and what it is/used for. The drug TBX-FREE says it makes one feel as if they just had a cigarette?